Contiguous, branched transmyocardial revascularization (TMR) channel, method and device

ABSTRACT

Improved methods and devices related to laser-assisted transmyocardial revascularization (TMR), and more particularly, to improved methods and devices for creating branched TMR channels through myocardium in which a single opening is made in an epicardial surface with a plurality of channel branches, having predetermined geometries extending into and through myocardium, depending therefrom. A method of creating branched TMR channels comprises piercing an epicardial surface mechanically or with laser energy, directing laser energy through the opening in a first predetermined angular orientation with respect to the epicardial surface to create a first channel and delivering laser energy in a second predetermined angular orientation to create a second branch. A plurality of branches can thus be created in a single channel structure. A guide block device allows an opening to be made in an epicardial surface mechanically or with laser energy and provides a structure for directing laser energy into myocardium in a plurality of channels depending from the opening. Rotating guide devices and finger held devices with rotating head means include a hand held device with an elongated wand-like handle portion, a rotating head portion and a hollow guide needle means. Preferred embodiments further comprise a laser delivery means advancing mechanism and guide needle rotating means.

This is a divisional application of Ser. No. 08/675,698 filed Jul. 3,1996, now U.S. Pat. No. 5,766,164.

FIELD OF THE INVENTION

The present invention relates to a surgical procedure known aslaser-assisted transmyocardial revascularization (TMR), and moreparticularly, to contiguous, branched TMR channels, including methodsand devices for creating them, which originate at a single point on orbelow the epicardial surface and develop along a plurality of radiating,ultimately independent paths thereby permitting capillary communicationand enhanced myocardial infusion of oxygenated blood, growth, healing,and other factors. These methods and apparatuses can be adapted for usein surgical applications throughout the human body or in animals forpiercing, infusion, vascularization or transmission of laser energy,drugs or other treatment therapies precisely, at predetermined positionsand to predetermined depths.

BACKGROUND OF THE INVENTION

Heart disorders are a common cause of death in developed countries. Themajor cause of heart disease in developed countries is impaired bloodsupply. The coronary arteries, which supply blood to the heart, becomenarrowed due to atherosclerosis and part of the heart muscle is deprivedof oxygen and other nutrients. The resulting ischemia or blockage canlead to angina pectoris, a pain in the chest, arms or jaw due to a lackof oxygen to the heart, or infarction, death of an area of themyocardium caused by ischemia.

Techniques to supplement the flow of oxygenated blood directly from theleft ventricle into the myocardial tissue have included needleacupuncture to create transmural channels (see below) and implantationof T-shaped tubes into the myocardium. Efforts to graft the omentum,parietal pericardium, or mediastinal fat to the surface of the heart hadlimited success. Others attempted to restore arterial flow by implantingthe left internal mammary artery into the myocardium.

Modernly, coronary artery blockage can be treated in a number of ways.Drug therapy, including nitrates, beta-blockers, and peripheralvasodilatator drugs (to dilate the arteries) or thrombolytic drugs (todissolve clots) can be very effective. Transluminal angioplasty is oftenindicated--the narrowed diameter of the opening or lumen of the artery,clogged with atherosclerotic plaque or other deposits, can be increasedby passing a balloon to the site and inflating it. In the event drugtherapy is ineffective or angioplasty is too risky, the procedure knownas coronary artery bypass grafting (CABG) may be indicated. Theprocedure requires the surgeon to make an incision down the center ofthe patient's chest and the heart is exposed by opening the pericardium.A length of vein is removed from another part of the body, typically theleg. The section of vein is first sewn to the aorta and then sewn onto acoronary artery at a place such that oxygenated blood can flow directlyinto the heart. CABG is a major surgical procedure which requires theinstallation of the heart-lung machine and the sternum must be sawedthrough.

Another method of improving myocardial blood supply is calledtransmyocardial revascularization (TMR), the creation of channels fromthe epicardial to the endocardial portions of the heart. The procedureusing needles in a form of "myocardial acupuncture" has been usedclinically since the 1960s. Deckelbaum, L. I., CardiovascularApplications of Laser Technology, Lasers in Surgery and Medicine15:315-341 (1994). The technique was said to relieve ischemia byallowing blood to pass from the ventricle through the channels eitherdirectly into other vessels perforated by the channels or intomyocardial sinusoids which connect to the myocardial microcirculation.The procedure has been likened to transforming the human heart into oneresembling that of a reptile.

In the reptilian heart, perfusion occurs via communicating channelsbetween the left ventricle and the coronary arteries. Frazier, O. H.,Myocardial Revascularization with Laser--Preliminary Findings,Circulation, 1995; 92 [suppl II]:II-58-II-65. There is evidence of thesecommunicating channels in the developing human embryo. In the humanheart, myocardial microanatomy involves the presence of myocardialsinusoids. These sinusoidal communications vary in size and structure,but represent a network of direct arterial-luminal, arterial--arterial,arterial-venous, and venous-luminal connections. This vascular meshforms an important source of myocardial blood supply in reptiles but itsrole in humans is poorly understood.

Numerous studies have been performed on TMR using lasers to borechannels in the myocardium. Histological evidence of probable new vesselformation adjacent to collagen occluded transmyocardial channels exists.In the case of myocardial acupuncture or boring, which mechanicallydisplaces or removes tissue, acute thrombosis followed by organizationand fibrosis of clots is the principal mechanism of channel closure. Bycontrast, histological evidence of patent, endothelium-lined tractswithin the laser-created channels supports the assumption that the lumenof the laser channels is or can become hemocompatible and that itresists occlusion caused by thrombo-activation and/or fibrosis. A thinzone of charring occurs on the periphery of the laser-createdtransmyocardial channels through the well-known thermal effects ofoptical radiation on cardiovascular tissue.

U.S. Pat. No. 4,658,817 issued Apr. 21, 1987 to Hardy teaches a methodand apparatus for TMR using a laser. A surgical CO₂ laser includes ahandpiece for directing a laser beam to a desired location. Mounted onthe forward end of the handpiece is a hollow needle to be used insurgical applications where the needle perforates a portion of tissue toprovide the laser beam direct access to distal tissue.

U.S. Pat. No. 5,125,926 issued Jun. 30, 1992 to Rudko et al. teaches aheart-synchronized pulsed laser system for TMR. The device and methodcomprises a device for sensing the contraction and expansion of abeating heart. As the heart beat is monitored, the device triggers apulse of laser energy to be delivered to the heart during apredetermined portion of the heartbeat cycle. This heart-synchronizedpulsed laser system is important where the energy and pulse rate of theparticular type of laser are potentially damaging to the beating heart.

U.S. Pat. No. 5,380,316 issued Jan. 10, 1995 and U.S. Pat. No. 5,389,096issued Feb. 14, 1995 both to Aita et al. teach, respectively, systemsand methods for intra-operative and percutaneous myocardialrevascularization. The '316 patent is related to TMR performed byinserting a portion of an elongated flexible lasing apparatus into thechest cavity of a patient and lasing channels directly through the outersurface of the epicardium into the myocardium tissue. In the '096 patentTMR is performed by guiding an elongated flexible lasing apparatus intoa patient's vasculature such that the firing end of the apparatus isadjacent the endocardium. Channels are created directly through theendocardium into the myocardium tissue without perforating thepericardium layer.

TMR is most often used to treat the lower left chamber of the heart. Thelower chambers or ventricles are fed by the more distal branches of thecoronary arteries. Distal coronary arteries are more prone to blockageand resulting heart muscle damage.

To date, TMR channels have been created surgically straight through theepicardial surface into the myocardium, or in the alternative,vascularly via catheter from the endocardium within a chamber straightradially outwards into myocardium. In either case, an essentiallysingle-ended channel is ultimately formed.

A need exists in the prior art for maintaining patency of TMR channels,for increasing blood flow in channels that are closed at the epicardium,or created percutaneously, for reducing trauma to the epicardial layerof the heart, and for creating multiple channels through a singleopening, particularly in areas where access and visibility are limited.

Thus, broadly, it is an object of the present invention to provide animproved method and device for laser-assisted transmyocardialrevascularization (TMR).

It is a further object of the present invention to provide a method forperforming TMR in which branched channels are created in the myocardiumthrough a single access opening thereby reducing trauma to the exteriorof the heart.

It is a further object of the present invention to provide a method forperforming TMR in which branched channels are created in the myocardiumto allow flow of blood and other factors through channel branches frommyocardial capillaries.

It is a further object of the present invention to provide a device forperforming TMR in which branched channels are created in the myocardium.

It is a further object of the present invention to provide a device forperforming TMR, particularly suitable for use in areas where access andvisibility are limited, in which branched channels are created in themyocardium, through a single opening, by providing a fiber advancingmechanism and a laser delivery means having needle orientation means.

It is a further object of the present invention to provide a device forperforming TMR in which branched channels are created in the myocardiumby providing a hand-held device with a fiber advancing mechanism and alaser delivery means with needle orientation means.

It is a further object of the present invention to provide a device forperforming TMR in which branched channels are created in the myocardiumby providing a finger-tip operated device with fiber advancing mechanismand a laser delivery means with needle orientation means.

SUMMARY OF THE INVENTION

A transmyocardial revascularization (TMR) channel structure defining apredetermined geometry comprising an opening in an epicardium of a humanheart, a first branch extending from the first opening into myocardium,and at least one additional branch into myocardium, the first branch andat least one additional branch in communication with each other. Apreferred embodiment of the TMR channel structure has at least one ofthe additional branches non-contiguous with the first branch at allpoints other than near the opening. A preferred embodiment of the TMRchannel structure further comprises a cavity disposed between andcommunicating with the first and at least one additional branch. Apreferred embodiment of the TMR channel structure further comprises atleast two additional branches extending from the first branch intomyocardium, thereby creating a plurality of communicating TMR channelsin preselected portions of myocardium. A preferred embodiment of the TMRchannel structure has at least one branch of the TMR channel arcuate inshape. A preferred embodiment of the TMR channel structure has at leastone branch of the TMR channel extending through endocardium.

A method for creating a branched transmyocardial revascularization (TMR)channel in a preselected portion of myocardium, the method comprisingthe following steps: (a) creating an opening in an epicardial layer of aheart ventricle; (b) delivering a first amount of laser energy throughthe opening at a first predetermined angle with respect to theepicardial surface so as to create a first branch in myocardium; and (c)delivering a second amount of laser energy through the first opening ata second predetermined angle with respect to an epicardial surface so asto create a second branch in the myocardium, the first and the secondpredetermined angles being different from each other, the first and thesecond branches in communication with each other at one or more points,thereby forming a contiguous, branched TMR channel. In a preferredembodiment of the method, step (a) further comprises the step ofdelivering sufficient laser energy to an epicardial surface to create atleast one hole therethrough. A preferred embodiment of the methodfurther comprises the step of delivering sufficient laser energy to atleast one branch to penetrate through an endocardial surface. Apreferred embodiment of the method further comprises the following step:(d) delivering additional amounts of laser energy through the opening atadditional predetermined angles with respect to the epicardial layer tocreate a plurality of branches in myocardium at angles different fromeach other, wherein the plurality of branches of the TMR channel socreated are in communication with each other to form a contiguous,branched TMR channel.

A method for creating a contiguous, branched transmyocardialrevascularization (TMR) channel in a preselected portion of myocardium,the method comprising the following steps: (a) creating an opening in anepicardial layer by mechanical piercing; (b) inserting a hollow guideneedle into the opening; (c) delivering a first amount of laser energythrough the hollow guide needle at a first predetermined angle withrespect to the epicardial layer as determined by an angular orientationof the hollow guide needle, so as to create a first branch of the TMRchannel in myocardium; (d) rotating the hollow guide needle within theopening of the epicardial surface to a second predetermined angularorientation; and (e) delivering a second amount of laser energy throughthe hollow guide needle at a second predetermined angle as determined bythe second angular orientation of the hollow guide needle, so as tocreate a second branch of the TMR channel. A preferred embodiment of themethod comprises the following additional step: (f) retracting the laserdelivery means such that a distal end of the laser delivery means doesnot extended past an opening at a distal end of the guide needle priorto the step of delivering a second amount of laser energy through thehollow guide needle at a second predetermined angle. A preferredembodiment of the method in which at least one branch of the TMR channelextends through endocardium.

A guide block device for a surgical transmyocardial revascularization(TMR) procedure, the guide block device comprising a body portion forplacement on an epicardial surface of the heart, the body portion havingupper and lower surfaces, an opening extending between the upper andlower surfaces, and a bearing surface surrounding and extending from theopening through the body portion and defining pivot-point means forangulation of a laser delivery means to create a contiguous, branchedTMR channel. In a preferred embodiment, the guide block device furthercomprises a hollow guide needle, the guide needle having a proximal end,a central axis, and a distal end sharpened for mechanically piercing anepicardial layer, the hollow guide needle directing the laser deliverymeans to deliver laser energy to preselected portions of myocardium.

A rotating guide device for creating branched transmyocardialrevascularization (TMR) channels in preselected portions of myocardium,the rotating guide device comprising a housing positionable on anepicardial surface adjacent a preselected portion of myocardium, thehousing portion having an upper surface, and a lower surface, rotatinghead means disposed within the housing, hollow guide needle meansoperatively connected to the rotating head means and having a centralaxis, a proximal end, and a distal end, the distal end sharpened formechanically piercing an epicardial layer, wherein the hollow guideneedle means directs a laser delivery device for delivery of laserenergy through the guide needle means and through the epicardial layerto preselected portions of myocardium at a first predetermined anglewith respect to the epicardial layer to create a first branch extendinginto myocardium, the laser delivery means retractable through the hollowguide needle means and the hollow guide needle means rotatable fordelivery of laser energy into myocardium at a second predetermined anglewith respect to the epicardial layer to create a second branch, thefirst and the second branches forming, in combination, a contiguous,branched TMR channel. In a preferred embodiment, the guide needle meansof the rotating guide device further comprises a curvature at the distalend so as to deflect the distal end of a laser delivery device to anangle with respect to the central axis of the hollow guide needle means.In a preferred embodiment, the rotating head of the rotating guidedevice is indexed with a predetermined number of angular positions suchthat the distal end of the guide needle is directed to a predeterminednumber of angular positions to allow the laser delivery means to deliverlaser energy into myocardium at predetermined angles with respect to anepicardial surface. In a preferred embodiment, the rotating guide devicefurther comprises a handle attached to the housing. In a preferredembodiment, the rotating guide device further comprises a stabilizationmeans forming a secure anchor point between the device and an epicardialsurface. In a preferred embodiment, the stabilization means of therotating guide device comprises a flexible bellows portion integral withthe housing portion thereby forming an evacuable chamber extendingsomewhat beneath the lower surface of the housing portion when placedadjacent the epicardial layer, and a vacuum port in communication with avacuum applying means such that when the rotating guide device is placedadjacent to the epicardial layer, the evacuable chamber can beevacuated, thus providing a vacuum seal between the rotating guidedevice and the epicardial layer. In a preferred embodiment, thestabilization means of the rotating guide device comprises the guideneedle means. In a preferred embodiment, the rotating guide devicefurther comprises a laser delivery means advancing mechanism mountedwithin the handle. In a preferred embodiment, the rotating guide devicelaser delivery means advancing mechanism consists of a laser deliverymeans retaining means and an actuator wherein the laser delivery meansretaining means holds the laser delivery means in a secure positionwithin the handle and the actuator allows the laser delivery device tobe advanced and retracted a predetermined distance through the handle.In a preferred embodiment, the rotating guide device laser deliverymeans advancing mechanism comprises an electric motor to advance thelaser delivery means a predetermined distance. In a preferredembodiment, the rotating guide device rotating head means comprises aworm gear assembly. In a preferred embodiment, the rotating guide devicehandle portion is elongated in the shape of a hand wand for convenientmanual control, the elongated handle having a proximal end through whicha laser delivery means can be introduced into the handle portion, thehandpiece further comprising a manifold for guiding the laser deliverymeans from the handle portion to the head means and into the hollowtubular opening of the guide needle means.

A guide needle for forming branched TMR channels comprising a hollowtubular body terminating in a distal tip curved to deflect a fiber opticlaser delivery means mounted therein.

Numerous other advantages and features of the present invention willbecome readily apparent from the following detailed description of theinvention and the embodiments thereof, from the claims and from theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-9 are channel geometry diagrams representative of cross-sectionviews of channels through the myocardium embodying principles of thepresent invention.

FIGS. 10A-10D are representations of a preferred embodiment of thedevice and method of use of the present invention.

FIGS. 11-14 are cross section and slight isometric views of guideneedles used in the preferred embodiments of the method and devices ofthe present invention.

FIGS. 15A-15D, 16A-16B are illustrative representations of a pivot-pointand flex-joint guide block device and method of use of a preferredembodiment of the present invention.

FIGS. 17-21 are views of a preferred embodiment of a rotating needle TMRhandpiece of the present invention.

FIG. 22 is an electronics block diagram for a rotating needle handpieceof the present invention.

FIGS. 23-28 are representative illustrations of preferred embodiments ofrotation drive devices of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As described above, TMR is a process of introducing holes, channels orsmall tunnels into and through parts of the myocardium and theepicardial and/or endocardial surfaces.

The present invention is intended for use with any medical laser. Inparticular, the Holmium laser is particularly suited to the presentinvention. However, any suitable laser source, pulsed or otherwise,could provide laser energy to the laser delivery means of the presentinvention for performing the method of the present invention. Likewise,the catheter and surgical equipment, including laser delivery means,referred to in the present document as well as that known and used inmedicine and other disciplines today and in the future, will be includedin the scope of this disclosure. Such laser delivery means include, butare not limited to, individual optical fibers as well as bundles offibers, rods, mirror configurations and other laser delivery means arewell described and will be useful in practicing the methods of thisinvention. It will also be understood that the preferred methods of thepresent invention are performed using the novel and unique devicesdescribed herein as well as any conventional mechanisms enabling anglingor rotation of the fiber optic tip to effect creation of the branchedchannels.

Preferred Channel Geometries

Prior art channels are generally single, straight pathways. Thecontiguous branched channels of the present invention are communicatingchannels. The communicating channels may be straight, curved in one ormore directions, or have internal corners of essentially any radius ofcurvature. While certain channel geometries will of course be moreadvantageous, either in terms of efficacy, length of time to perform theprocedure, degree of complication of equipment required, skill level ofsurgeon, etc., virtually any channel geometry could in fact be producedin the heart. It will be understood that while the channels describedherein as well as the methods for producing them are contemplated asoriginating at or just below the epicardial surface, they will generallycontinue through the myocardium and through the endocardium, althoughthe channels could terminate at some point within the myocardium,providing thereby a "stimulus". All such "channel" embodiments will beexpressly incorporated herein unless otherwise expressly delimited byspecific limiting language, and the holes or channels contemplated willbe primarily through both the myocardium as well as the endocardium.

FIGS. 1-9 are channel geometry diagrams representative of cross-sectionviews of channels through the myocardium embodying principles of thepresent invention. FIG. 1 shows a conventional channel 100. The channeldevelops along a direction or axis A essentially normal to theepicardial surface 102 of the heart into the myocardium 104. In FIG. 2,the "2D inverted Y" channel has one opening 110 at the epicardialsurface. The channel is symmetrical and easily adaptable to a 3Dgeometry. There is a potential for creating a large cavity at thejunction 112, for example, by extending the central branch 114 slightlybelow the junction, which will provide a channel with a larger voidvolume, eliminate sharp angles and increase the potential for enhancedblood circulation therethrough. Furthermore, according to fluidmechanics the pressure drop in blood flowing from the inside of a heartchamber through the endocardium along a channel through a first branchand through a second branch will be less if the cavity is larger or thedegree of angle in the corners is less. It will be understood,therefore, that the term "cavity" will include the entire region betweenthe opening in the epicardial surface and the bottom of the centralbranch, including the central branch and the junction with the two ormore branches depending therefrom. In FIG. 3, the "curved inverted Y"branched channel also has one opening at the epicardium surface 120, andcan be symmetric and adapted to a 3D geometry. Additionally, a largercavity 122 may be provided near the junction of the main channel,resulting in a reduced risk of causing thermal damage in the junctionregion.

It will also be understood that the depth of penetration of the initialchannel below the epicardial surface can be varied by the surgeon or byoperating options of the devices of the present invention. The initialpart of the channel can be very short, such that the junction betweenbranches depending therefrom is closer to the epicardial surface or isdeeper within the myocardium. Operator adjustments can be made to thedepth of penetration of the guide needle or laser delivery means byprovision of a depth stop means. Such depth stop means will control thesubepicardial distance through which not only the guide needle orpiercing needle can be advanced but also the distance through which thelaser delivery means can be advanced. Of course, as will be apparent,the degree of rotation of the guide needle or other piercing means canbe adjusted infinitely or according to certain pre-set indexed rotationstops or indents.

The following table is a list of the names associated with variouschannel geometries. It will be understood that these names are intendedto be descriptive of certain embodiments and are not, therefore,limiting in any way.

    ______________________________________                                        FIG.           Preferred Channel Geometries                                   ______________________________________                                        1              straight or conventional                                       2                2D inverted Y                                                3                2D curved inverted Y                                         4                2D or 3D inverted V                                          5                3D squid shape                                               6                2D twig                                                      7                3D twig                                                      8                3D curved, inverted Y                                        9                2D or 3D capillary channel                                   ______________________________________                                    

An important consideration when forming a plurality of channels having aplurality of branches is the overall rise in temperature of thesurrounding tissue. It will be understood that while a great number ofbranches could actually be lased, all at different angles to the axisnormal to the surface of origin, the heat produced may be damaging tothe tissue surrounding the channels, especially in the area of thecavity or other junction between individually-bored or lased channels.Increasing the delay between the boring of individual channels would ofcourse allow for dissipation of excess heat.

Another consideration is direction of blood flow within the heart andcoronary arteries and placement of the channels. Since there is flowthrough the heart and coronary arteries, at least during various stagesof the heart's cycle, a pressure gradient can be found through the heartand through individual chambers. Providing channels with multipleopenings in the endocardium aligned with or oriented in the direction ofblood flow will increase the blood flow through the patent channels.

It will be understood that the devices of the preferred embodiments ofthe present invention are particularly suited to both open heart surgeryas well as the more recently popular minimally invasive surgery (MIS)techniques. It will be understood that in MIS procedures, since reducingthe size of the opening in the chest cavity is one goal, devices must beappropriately designed to allow for as much control as possible whileminimizing the size of access pathways to the heart.

FIGS. 10A-10D are representations of a preferred embodiment of a deviceand method of use of the present invention for using a needle to piercethe epicardium. In FIG. 10A, the needle 150 is inserted through theepicardial surface 152, optionally through a guide block 154, mandrel orother stabilizing means. The curved needle has an opening 156 which canbe oriented in a predetermined direction with regard to the myocardium158 to be vascularized. In FIG. 10B, a laser delivery means 160, such asa fiber or fiber bundle is introduced through the lumen of the needle. Acurvature which initiates with the distal tip 162 of the needle ismaintained by the optical fiber or fiber bundle resulting in a firstcurved channel 164 being formed along a first axis B, forming an angle Cwith the normal to the epicardial surface. As shown in FIG. 10C, thelaser delivery means is retracted into the needle, the needle is rotatedthus orienting the opening away from the first channel, and the laserdelivery means is again advanced to form a second curved channel 170. InFIG. 10D, the laser delivery means and needle have both been removed andthe resulting branched channel 172 remains. The method of forming thechannel can be modified as the surgeon prefers, but will generallycomprise a combination of fiber advancement and laser delivery. It willbe understood that a cavity below the epicardial surface can be formedby directing an extra pulse or two of laser energy at the junction ofthe branches. This cavity will increase the patency of the channel aswell as the blood flowthrough capacity. Further, it will be understoodthat a single optical fiber as well as a fiber bundle can be used, andthe fiber or bundle preferably includes a bias member to facilitateflexibility and assist in navigation through the curved needle. A biasmember may include, for example, a piece of nitinol or other malleableor memory wire within the bundle of fibers or a heat-treated plasticmaterial piece or jacket around the bundle preset in an arc. A pre-bentneedle also reduces friction and improves tactile sensation as the fiberis advanced.

Rotating Guide Needle

FIGS. 11-14 are cross section and slight isometric views of guideneedles used in preferred embodiments of the method and devices of thepresent invention. FIG. 11 is a cross section view of a needle with astraight cut end opening 200 opposite the curvature 202 of the distaltip. FIG. 12 is a slight isometric view of the same embodiment. FIG. 13is a cross section view of a needle with a conical cut end opening 204opposite the curvature 206. FIG. 14 is a slight isometric view of thesame embodiment. It will be understood that the distal end of the needlewill be defined as the end from which the laser delivery means extendsso as to lase a channel into the myocardium and comprising the conicalor flat cut piercing point and curvature for deflecting the distal endof a laser delivery means. The proximal end of the guide needle will beunderstood to refer to the end into which the laser delivery meansenters the guide needle. Typically, needles are cut from suitable stockmaterial or otherwise manufactured. The radius at the end which deflectsthe laser delivery means at an angle may be formed by rolling thematerial over a 3/8 or 1/2 inch mandrel or other form. Typically, theangle D formed between the straight cut end plane and the needle axis,or the angle E formed between the conical cut plane and the needle axis,will be, in a preferred embodiment, between about 3-10°. The conical cutend tip can be formed by starting with a flat cut end tip, producing abend at the end of the needle using a mandrel, spinning the needle aboutit's central axis and turning the end cut surface over a radius ofcurvature to form arced surface 208 having a radius of curvature F. Thiscan be done with a dremel tool or other mill, lathe, etc. It will beunderstood that the internal shoulder of the opening of the needle nearthe laser delivery deflecting curvature will be rounded or otherwisesmooth enough so as not to damage or bind the fiber or fiber bundle uponinsertion or extraction. Another method of forming an efficient piercingtip is to form the bend in the tip of the needle, spin the needle aboutan axis slightly off the central axis of the needle by between about6-8°, and then grinding the end cut surface with a conical shapedsurface. This provides a more durable, efficient piercing needle tip. Inthe preferred embodiments, due to the fact that the outside diameter ofthe fiber or fiber bundle will necessarily be smaller than the insidediameter of the needle tip to be efficiently extended and retracted, thetheoretical fiber deflections by the needle tips will be between about25-30° whereas the resulting actual bend of the laser delivery devicewill be less than that.

In a preferred embodiment, the guide needles of the present inventionhave heating means so that the tip of the needle is hot as it piercesthe surface of the epicardium to reduce or eliminate bleeding bycauterizing the tissue opening of the pierced channel. Thereafter, asthe laser delivery means is urged through the needle and is used to lasea channel or channel into the myocardium, excessive bleeding will notinterfere with visibility in the area. The heater means may include asmall resistance heater to heat the tip of the needle by passing anelectrical current through it. Another embodiment uses an absorptiveelement on the needle, such as a stainless steel tip, preferably at ornear the fiber deflecting curvature, so as to absorb a part of thetransmitted laser energy to heat the tip sufficiently. Other heatermeans will be known to those skilled in the art.

Pivot-point Guide Block

FIGS. 15A-15D are illustrative representations of a pivot-point guideblock device and method of use of a preferred embodiment of the presentinvention. The guide block 220 is placed onto the epicardium and aneedle 222 is advanced until it pierces the epicardial surface 224. Theguide block has a frustoconical internal bearing surface 226. As theneedle and fiber mounted therein is tilted to one side as in FIG. 15B,it is brought to bear against the bearing surface to point downward intothe myocardium 228 in direction G, at an angle of H with the normal tothe epicardium. In this embodiment, a needle which does not deflect thedelivery end of the laser delivery means can be used. In FIG. 15C, thefiber 229 or other delivery means has been retracted and the fiber wastilted to another orientation biased against the bearing surface. Inthis position, the fiber is again advanced and a second channel can beformed in a direction I at an angle J with respect to the first branch230. The resulting multi-branch channel 232 will be formed therebyoriginating just below the epicardial surface. This "pivot-point"concept can be used with a rotating needle device, described below, tocreate 2-dimensional or 3-dimensional branched channels. Alternatively,the guide block may be used as support for a laser piercing apparatus inwhich case the laser tip is rotated to create a double channel with theblock acting as a flex or pivot joint.

FIG. 16A is a cross section view of a guide block with flex-joint tipand bellows for vacuum-assisted stabilization of the device. The guideblock has a housing portion 290 with a flexible bellows 292 extendingdownward and outward from the perimeter of the housing. Above the guideblock there is a flex joint 293. This joint, for instance a ball andsocket-type joint, allows the laser delivery means to be positioned atan angle for access to areas where the delivery means cannot bepositioned upright prior to channeling through the myocardium. Athin-walled portion 294 of the bellows will be made of rubber or someother flexible material. The bellows-equipped guide block sets on top ofthe epicardial surface 296. As a vacuum is applied to the inside of thebellows, through a vacuum port 298 in a preferred embodiment, thethin-walled portion of the bellows collapses, holding the bellowsportion firmly secured to the epicardial surface. A flex-joint tip 300is provided at the distal end of the laser delivery means path. Anoptical fiber 302, fiber bundle or other laser delivery means can thenbe extended through the flex-joint tip and used to lase a branch of achannel into the myocardium. Such vacuum-assisted apparatus andprocedures are more fully described in co-pending U.S. patentapplication Ser. No. 08/628,849 filed Apr. 5, 1996, now U.S. Pat. No.5,738,680.

Based on the foregoing description of the rotating guide block and thepivot-point guide block, it will be understood that the guide blockequipped with a bellows can have an internally rotating portion or othermeans, to be described below, to re-orient the flex joint tip to createa second branch of the original channel. Furthermore, a guide needlecould be placed at the distal end of the laser delivery means path suchthat when a vacuum force is applied the collapsing bellows drives thetip of the guide needle through the epicardial surface at apredetermined angle to the epicardial surface and to other channels. Itwill be understood that the bellows with suction attachment formaintaining the laser delivery means (or guide block or pivot block orother rotating means) is but a single stabilizer means for attaching thedevice to the heart at a given position during the procedure of lasingan individual channel. As the heart beats this suction device or otherstabilizer means assists the surgeon to counteract the beating heart'smotion. Individual practitioners may find that the stabilizer means isespecially useful in minimally invasive surgical procedures, as opposedto open heart procedures, wherein locating a device precisely adjacent aspecific region of the epicardium and holding it there during theprocedure may otherwise be difficult. The stabilizer means will alsoinclude an external retractor or clamp-type feature such that the targetspot is held in place but allowing the mass or greater bulk of the heartto move freely.

FIG. 16B is a cross section view of a guide block with flex joint andbellows for vacuum-assisted stabilization of the device. In thisembodiment, the flex joint 303 is located within the flexible bellows304. In this alternate embodiment, the flex joint for rotating thehandle portion is located nearer the surface of the heart and theflexible tip is omitted. A needle 305, or guide tube, extends to aposition just above the epicardium 306. In this way, a laser deliverydevice such as an optical fiber can approach the epicardium and boreholes therein at any angle within a given range of angles L with respectto the normal to the epicardial surface.

Rotating Needle TMR Handpiece

FIGS. 17-21 are views of a preferred embodiment of a rotating needle TMRhandpiece of the present invention used to facilitate the formation ofcommunicating channels. FIG. 17 is a graphic representation of themethod of use of a handpiece of the present invention. The handpiece 310can be held by the surgeon with one hand. An opening is made in thechest cavity using a conventional method and the head portion 312 isplaced onto the heart 314 at the desired position. The head portionserves the purpose of a guide block in that the head portion can bepositioned and secured to the heart with or without vacuum assistance.The head portion also may contain a guide needle. A thumbwheel 316 isused by the surgeon to advance the fiber or fiber bundle into thechannel being created. A preferred embodiment also comprises an internalrotating retaining portion, explained below, which rotates after thefiber has been advanced, a channel created and the fiber and/or needleextracted.

FIG. 18A is a top isometric view of a preferred rotating needlehandpiece of the present invention. The handpiece comprises a handleportion 320 and a tail portion 322. A thumbwheel 316 is used foradvancing the fiber, bundle or other laser delivery means. A neckportion 324 is joined to the handle portion and may include a pivotingjunction 326. As the fiber extends from the tail, through the handleportion and into the neck portion, the fiber is directed into a manifold328 in order to effect the change in direction necessary to direct theoptical fiber or bundle out of the head portion. It will be understoodthat the manifold structure could be manufactured integrally with theconstruction of the neck and head portion, such as by an extrusion orinjection molding process. Such J-grip TMR apparatus is more fullydescribed in co-pending U.S. patent application Ser. No. 08/607,782filed Feb. 27, 1996, now U.S. Pat. No. 5,713,894.

FIG. 18B is a top isometric view of a preferred rotating needlehandpiece of the present invention with a fiber depth adjustment. As inthe previously disclosed embodiments, a thumbwheel 330 is used toadvance a laser delivery means, such as an optical fiber, through thehandpiece. The distance which the fiber is advanced is controlled by alaser delivery means side slider-type depth adjust means 332. Themaximum depth of the channel which is to be created by the handpiece canbe set precisely and conveniently by locating the side slider at theappropriate axial position, as indicated by a scale or other referencemeans 334. In a preferred embodiment, the slider mechanism controls, andvisually shows, the depth the fiber may be advanced, and adjusts thedepth stop control. It will be understood that the handpiece may have asingle-sided or a double-sided slider depth adjust means. Furthermore,other means for adjusting the depth of advancement of an optical fiberor other laser delivery means through the handpiece will be apparent tothose skilled in the art.

FIG. 19 is a side elevation view of a preferred rotating needlehandpiece of the present invention and FIG. 20 is a top sectional viewof a rotating needle handpiece of the present invention taken throughsection 20. It will be understood that the optical fiber 338 or otherlaser delivery means will enter at the proximal end 340 of the device,travel through a guide tube 342, and exit a guide needle 344 at thedistal end of the device. In a preferred embodiment, a small battery 346seated in a battery cradle 348 and operated by a micro switch 350 willpower a circuit board 352 and needle rotating motor 354. Manualoperation of the thumbwheel 356 will advance and retract the opticalfiber or other laser delivery means coupled to a rack portion358--individual gears on the thumbwheel engage the geared rack portion.Alternatively, fiber advance can be automated using a motor. Aproximally located bulkhead 360 and a distally located bulkhead 362 areused to mount the internally disposed fiber advance mechanism as well asthe head rotating mechanism in the TMR handpiece or wand. In a preferredembodiment, the head of the TMR wand is positioned on the heart musclesuch that a guide needle pierces the epicardial surface at the intendedchannel site. The laser delivery fiber is advanced, utilizing thethumbwheel, as a channel is lased into the myocardium. The thumbwheel ismoved in the direction shown by double-headed arrow K. It will beunderstood that the thumbwheel portion can be manufactured to directlyadvance the fiber without drive reducing gear, or conventional gearreduction can be utilized so as to advance the fiber a predetermineddistance in response to a predetermined degree of angular rotation. Inthe automated embodiment, the thumbwheel is an electrical actuator withcontacts which will complete an electrical circuit to move the fiber inthe desired direction. The precise relationship between the degree oflongitudinal motion and angular rotational movement can be selected asdesired, with the precise engineering known to those skilled in the art.Once the first branch of the channel has been created, the thumbwheelwill be used to retract the fiber. Thereafter, the guide needle can bere-oriented. Rotation of the guide needle can be actuated by controlcircuitry in response to movement of the thumbwheel to its rearmostposition in which case the needle rotation motor is in a circuit withthe thumbwheel. Alternatively, a separate switch can be installed on thehandle or other portion of the TMR wand to control the angular rotationof the TMR head portion and guide needle. In a preferred embodiment, theguide needle rotation motor is coupled to a gearhead 364. A shaft 366extends through the neck of the handpiece, from the gearhead to arotating portion 368.

FIG. 21 is a detail front sectional view of a rotating needle handpieceof the present invention taken through section 21. As described, thedevice comprises both a fiber advancing mechanism and a guide needlerotating means, optionally and preferably in various embodiments, withassociated electronics, sensors, stops, actuators, power sources, etc.The needle holder 370 is integral with a pinion gear 372 which is actedon by a worm gear 374. As the worm gear is advanced in direction L, thepinion gear 372 rotates with the needle holder 370 and the needle 344,all three in direction M. As described, the preferred embodiment has anautomatic needle rotation and angle extending synchronizationelectronics system, such that the thumbwheel comprises an actuator andsensor to detect the length of fiber advancement. Controllers rotate theneedle a predetermined angular degree.

FIG. 22 is an electronics block diagram for a rotating needle handpieceof the present invention. For representative purposes, the optical fiberor fiber bundle 600 is shown attached to a fiber advance mechanism 602shown in a forward position. The switch can also be moved into a rearposition 604. A switch block 606 is adjusted such that before amechanical or other linkage 608 on the fiber advance mechanism reaches amechanical depth stop 610, a sensor 612 at a certain position willactivate an audible alarm 614. This audible alarm will advise thesurgeon with regard to the depth of penetration of the optical fiber soas to achieve uniform depth of penetration and precision in channelformation throughout the procedure. The alarm could also be visual orsensory, or otherwise integrated with other intelligent control.Associated control electronics comprise controller 616. This controllercomprises a printed circuit board, pre-programmed, programmable orsemi-programmable micro-controllers, other inputs or outputs, and otherassociated electronics. A power source 618 such as a battery is attachedto the controller and provides power to the alarm as well as a smalldirect current motor 620. This small motor toggles forward and reversedepending upon a signal produced by a motor activation and toggledirection selection switch 622. This switch is activated when the depthadjust mechanism is in the rear position. A preferred embodimentutilizes a small motor rotation indicator LED 624 or other visual,sensory or audible indicator. The switches of the device are eithermechanical, Hall effect, optical or other, with the motor current andvoltage either predetermined or variable. Various types of alarms willbe known to those skilled in the art including small lights, audiblealarms, vibrating components, diodes, other electronic means orotherwise. It will be understood that while the preferred embodimentincludes mechanical linkages, these mechanical components can bereplaced with electronic or other actuated systems for fiber advance aswell as needle rotation. An additional audible alarm may be provided ata different frequency to signal needle rotation.

Various embodiments for accomplishing rotation of the needle in therotation drive will be known to those skilled in the art. Any mechanicalhead rotation means, for example rack and pinion assembly, worm gears,actuator rods, torsion springs, etc. will be adaptable to the presentinvention.

Finger-tip Operated TMR Device

FIGS. 23-28 are representative illustrations of preferred embodiments ofrotation drive devices of the present invention designed to be held byone or two fingers with the remaining fingers and device acting as aheart retractor when used to approach the inaccessible posterior side ofthe heart. FIG. 23 shows a top perspective view of a finger-tip operatedTMR device. It will be understood that the fiber 500 can be fed into andthrough the device either through a horn portion 502, other handle orsupport means particularly for TMR on the back side of the heart, ordirectly through an opening 504 on the upper portion 506 of the device.Opening 504 is particularly useful in high access areas and allowsstraight fiber advancement thereby reducing drag. In another embodimentof the present invention, the TMR device is held by one hand while thelaser delivery means is inserted through the TMR device with theopposite hand or by an assistant. The hand used for insertion operatesthe laser advance mechanism trigger, such as a thumbwheel 508. Themanual feed system also utilizes a finger-tip operated button 510 toeffect needle rotation. The low profile of the rotating handpiece is keyfor use in confined spaces. FIG. 24 shows a top perspective of awrist-held finger-tip operated TMR device. While the fingertips are usedin a described fashion to control a push-button, the device utilizes astrap portion 520 for stabilization and for freeing the rest of thefingers for retraction of the heart for posterior wall approaches.

FIGS. 25-27 are upper, lower and exploded isometric views of twopreferred embodiments of finger-tip operated TMR devices of the presentinvention. FIGS. 26 and 27 show a housing 530 or other protectivecovering is manufactured of a suitable, lightweight, autoclavable orotherwise sterilizable material with a suitable surface texture to allowthe surgeon to grip the device during the procedure in the presence ofblood or other fluids. A horn 532 or other hollow opening or extendingstructure, serves as a first path to feed an optical fiber through thedevice, through insert 533. A fiber or other laser delivery means canalso be inserted into the device through conical portion 534 on theupper portion of the housing. The conical portion has a small hole onthe inside through which the fiber can be advanced. In a preferredembodiment, the conical portion includes a flange 536 which serves tokeep the device securely positioned in a surgeon's hand when thesurgeons fingers are slid between the housing and the flange. Thefinger-tip controlled push button 540 is mounted inside the housing andengages with a rack 542 and a spring 544. When desired, depressing thepush button moves the rack, retained in place on two pins 546 extendingthrough slot 548, in an axial direction. The teeth of the rack engagereducing gear 550 which is mounted on pin 556. The teeth of the reducinggear engage with pinion gear 552. Rotating head 554, pressed onto orotherwise fixed to the pinion gear, rotates in unison with the gearassembly and with guide needle 557 retained therein. The rotating headrides in the center 558 of a chassis portion 559 of the device. It willbe understood that the chassis portion serves primarily to retain theintegrity of the assembly, as may be necessary. The overall dimensionsof a preferred embodiment of the present invention is about 3 inches indiameter, about 41/2 inches long to the end of the horn, and only about1 inch tall, not including the slightly extending needle. The firstopening 560, through the hollow tubular section 562 of the horn or otherhandle serves as a path to advance the fiber through the device.

The preferred single entry port embodiment shown in FIG. 25 also employsa finger or thumb activated needle rotation button or bar 510 set intothe lower portion 664 of the housing 530 and is particularly suitablefor minimally invasive surgery (MIS) procedures such as TMR from theposterior surface of the heart. Such posterior- and lateral-aspectprocedures are more fully described in co-pending U.S. patentapplication Ser. No. 08/627,704 filed Mar. 29, 1996, now U.S. Pat. No.5,725,523. A transparent or semi-transparent tube 650 with graduatedmarkings 652 extends from the upper portion. In a preferred embodiment,this tube twists off forming an open side port. The device is heldbetween the index and the middle fingers and the remaining fingers ofthe same hand are available for retraction and stabilization. A depthstop 654 is attached to the optical fiber or fiber bundle 500, the depthstop being adjustable with positioning means 656, such as a threadedclamping mechanism on the fiber, such that the maximum depth ofpenetration of the laser delivery means can be controlled. The depthstop is positioned at a predetermined position on the optical fiber.Additionally, a detent 658 such as an integrally formed bead or otheraffixed component prevents the optical fiber from being fully retractedfrom the device. The graduated markings on the flexible or semi-flexibletube serving to provide the surgeon with a visual indicator as to thedepth of penetration during channel formation. The upper portion 660will pivot about joint 662 such that the surgeon can efficientlyposition the lower housing 664 without restriction caused by apredetermined orientation of the laser delivery means. The rotatableneedle may be retractable and scallops may be provided in the housing,and on the button, to facilitate gripping, and for other designpurposes. Furthermore, it will be understood that the lower surface 561of the TMR device may also be made of a non-slipping material such astextured metal or rubber, and may also have a dimpling or raised patternthereon to facilitate secure placement of the device during operation.

FIG. 28 is an alternate exploded view of the needle rotating mechanismgearbox of finger-tip operated TMR device of the present invention. Agear retainer 700 houses a plurality of gears 702 rotating about aplurality of axles 704. A button 706 is disposed inside a buttonretainer 708 such that it bears upon a rack gear 710. A mechanical stopelement 712 also serves as a spring screw retainer. Stop screw 714 andspring tension adjustment screws 716 act upon the mechanical stopelement and spring 720. A plurality of fasteners 718 hold the assemblytogether.

Various embodiments for accomplishing rotation of the needle in therotation drive will be known to those skilled in the art. Any mechanicalhead rotation means, for example rack and pinion assembly, worm gears,actuator rods, torsion springs, etc. will be adaptable to the presentinvention.

It will be understood that any of the embodiments described herein inwhich a guide needle or other piercing means is followed by a laserdelivery means, it will be an optional feature to provide a rotationinterlock system. Such interlock system will prevent needle rotationbefore the fiber is retracted or otherwise withdrawn from the opening.This will prevent injury to the heart. The interlock will ensure thatthe guide needle will not rotate prior to withdrawal of the laserdelivery means into at least the shaft of the needle.

While the principles of the invention have been made clear inillustrative embodiments, there will be immediately obvious to thoseskilled in the art many modifications of structure, arrangement,proportions, the elements, materials, and components used in thepractice of the invention, and otherwise, which are particularly adaptedto specific environments and operative requirements without departingfrom those principles. The appended claims are intended to cover andembrace any and all such modifications, with the limits only of the truespirit and scope of the invention.

We claim:
 1. A method for creating contiguous branched transmyocardialrevascularization channels comprising:a) positioning a guide devicehaving a rotating distal head in combination with a hollow piercingelement having a curvature at a distal end, on an epicardial surfaceadjacent myocardium; b) piercing the epicardial surface with thepiercing element to create an entry point; c) deflecting a laser energydelivery device through the curvature of the piercing element intomyocardium at a predetermined angle with respect to the epicardiallayer; and d) creating a first angled channel in myocardium.
 2. Themethod of claim 1 further comprising:e) retracting the laser energydelivery device into the hollow piercing element; f) rotating thepiercing element; g) advancing the laser energy delivery device intomyocardium from the entry point to create a second channel.
 3. Themethod of claim 2 wherein the rotating distal head is indexed with apredetermined number of angular positions and further comprising step h)repeating steps e) through g) and angling the distal end of the piercingelement to a number of angular positions to allow the laser energydelivery device to deliver laser energy into myocardium at predeterminedangles.
 4. A method for forming angled myocardial revascularizationchannels comprising:a) positioning a distal tip of an apparatus having adistal rotating orientation member in combination with a curved hollowneedle on a heart surface adjacent a preselected location of myocardium;b) perforating the surface to create an access opening; c) curving adistal end of a laser energy delivery device through the needle throughthe perforated surface into myocardium at a predetermined angle withrespect to the surface; and d) transmitting laser energy from the distalend of the laser energy delivery device into myocardium.
 5. The methodof claim 4 further comprising step e) rotating the orientation member toform a multi-ended channel with the access opening.
 6. The method ofclaim 4 further comprising step e) rotating the orientation member toform a plurality of channel branches from the access opening, havingpredetermined geometries extending into and through myocardium.
 7. Themethod of claim 6 further comprising step f) directing laser energy intoa junction of the plurality of channel branches to create a cavity. 8.The method of claim 4 further comprising a laser energy delivery devicehoused in and translatable through the apparatus and step b) perforatingthe surface with laser energy.
 9. The method of claim 4 step b)perforating the surface mechanically with the curved hollow needle. 10.The method of claim 9 the apparatus further comprising a heatingmechanism operatively coupled to the needle and further during step b)cauterizing the perforated surface opening.
 11. The method of claim 4the apparatus further comprising an automated advancing mechanismoperatively coupled to the laser energy delivery device and during stepc) advancing the laser energy delivery device automatically to apredetermined depth in the myocardium.
 12. The method of claim 4 theapparatus further comprising a manual advancing mechanism operativelycoupled to the laser energy delivery device and during step c) advancingthe laser energy delivery device manually to a predetermined depth inthe myocardium.
 13. A method for forming multiple transmyocardialchannels with a single entry point comprising:a) tilting a hollowpiercing element and laser energy delivery device combination against afirst surface of a guide device having a plurality of frustoconicalinternal bearing surfaces, said guide device placed on a heart surfaceadjacent myocardium; b) piercing the surface with the piercing element;c) advancing the laser energy delivery device through the piercingelement to create a first channel in myocardium; d) retracting the laserenergy delivery device into the hollow piercing element; e) orientingthe piercing element against a second surface of the guide device;creating a second channel at an angle to the first channel inmyocardium.
 14. A method for creating contiguous branchedtransmyocardial revascularization channels comprising:a) positioning aguide device having a distal head in combination with a hollow piercingelement having a curvature at a distal end, on a heart surface adjacentmyocardium; b) inserting the piercing element through the surface andinto myocardium; c) advancing and deflecting a laser energy deliverydevice through the curvature of the piercing element into myocardium ata predetermined angle with respect to the surface; and d) creating afirst angled channel in myocardium.